One of the most commonly replaced and expensive components in conventional electrostatographic copiers and printers is a fusing roller. It is a costly item which wears out rapidly. It is generally replaced by a serviceman who must connect the roller to a suitable drive, locate temperature sensors, heating lamp, and one or more skives and a fusing oil applicator at critical positions near or in contact with it.
Japanese Patent Application 63-107319 (1988), laid-open Nov. 7, 1989 (1-277271), shows a fuser in which a large portion of the entire fuser is replaceable in a single unit. The single unit includes both rollers and skives for each roller. It has the substantial disadvantage of replacing a more durable pressure roller assembly with the more easily worn out fusing roller.
When the fusing roller begins to show signs of wear, image quality has a tendency to deteriorate. This may indicate to a serviceman that the fusing roller should be replaced. However, other components of the image-forming apparatus also have an effect on image quality. A less highly trained operator, and in some instances, even a highly trained serviceman, may not know which component to investigate first when an image quality problem occurs. Servicemen commonly keep track of the number of images or the time lag between replacement of the fusing roller as a help to deciding whether replacement of the fusing roller is appropriate. This also can be used for preventive maintenance even before substantial reduction in image quality is observed.
Personally keeping track of the usage of a fusing roller is impractical for items that are to be serviced by a less highly trained operator.